Sun is a clean renewable source of energy. One of the effective usages of Sun's energy is concentrating its light on a target via reflective (mirrors) or refractive (lens) concentrators. We can concentrate sunlight using reflecting mirrors, refraction (lens), parabolic mirror or lens, one big, or large number of smaller ones, on a slab, or on double slabs, tiltable, moveable, or with rotation. The target can be solar cell, water heating reservoir or pipe, fuel cell reactor, Photosynthesis element, etc. We would produce under 1.7 cents/kWhr, for power generation, without the tolls on the environment.
In order to collect more energy, it is advantageous to keep the Alpha to a small value, even when sun is moving, as shown in FIG. 1. This often requires aligning the vertical axis of the reflective or refractive elements toward the sun, such as tilting or moving those elements, when the sun moves.
The following types of concentrators are commonly used to maximize the collected sunlight energy:
1. Reflective or refractive element (panel/surface/plate/dish)
2. Array of small parabolic reflective or refractive elements on a flat-panel (dish)
3. Array of small flat reflective or refractive elements on a parabolic-panel (dish)
All the above panels or dishes usually have tracking systems that track the sun and point the dish toward the sun. The above mentioned concentrators suffer from the fact that large and heavy panels (dishes) need to move constantly to track the sun. Such kind of movement requires electric motors and gearbox, which consume power and are prone to failure.